"At the moment I do not believe the New Zealand public is prepared to move on prohibition for the simple reason that they see removing prohibition as support for people smoking drugs," he said.
"I do not support people smoking drugs ... but what I do support is opening up the conversation about what prohibition has done to fund gangs.
"I think that's something we should be prepared to talk about. It shouldn't be scary to talk about it."
Mr Seymour was responding to the Government's announcements today about new anti-gang measures.
Earlier today the Government has launched two experimental pilot programmes in regions known for gang activity, as a new report shows that the long-term cost of social support for gang members is more than $700 million.
That cost mainly came from welfare payments, because nine out of 10 gang members were found to have received a main benefit at some point. But there were also large costs for child protection.
The Ministry of Social Development (MSD) collected information about nearly 4000 known gang members as they came into contact with social services.
The data was now being used to target gang members and their families dependence on Work and Income and Child, Youth and Family (CYF).
The findings show that gang members spent an average of 8.9 years on welfare, mostly the jobseeker benefit, and about 7000 dependent children were in families which relied on income support.
More than a quarter of gang members had allegedly abused or neglected their children.
The total "lifetime-to-date" costs of welfare and social support for gang members and their children was estimated to be $714 million.
Social Development Minister Anne Tolley said the Government was now aiming to break intergenerational gang involvement and cut related social costs.
"Gang life ruins families, and the social cost through domestic violence and child abuse is unacceptable," she said.
Two pilot programmes in the Bay of Plenty and the East Coast will experiment with new forms of social services for gang members' partners and children. The programmes will offer intensive support, education and job support, and youth mentoring, at a total cost of $1.1. million.
The MSD study found that nearly 40 per cent of gang members lived within the two targeted regions.
It also provided some details on the make-up of New Zealand gangs. About 86 per cent of members were patched, 77 per cent were Maori. and they had an average age of 40.
The Mongrel Mob and Black Power made up two-thirds of all gang members.
The pilot programmes were part of a broader Government crackdown on gangs announced ahead of the 2014 election.
The policy was initially based on incorrect data, which significantly overestimated the scale of gang members criminal offending by including all offences committed by gang "associates".
The MSD report did not collect data from gang associates or members of youth gangs.
Another part of the anti-gangs policy is a dedicated intelligence centre run out of police national headquarters.
Police Minister Judith Collins today said that the centre was now operational and providing information which disrupted illegal activity and identified members and associates who wanted to get away from the gang life.
The minister released an example of the kind of intelligence the centre was collecting - a family tree which had links to gangs. The example was fictional, but was based on agencies' records of gang families.
It shows that a 71-year-old woman and long-term beneficiary had nine children to two partners, one of them a gang member.Of those nine children, eight were on welfare, three were victims of family violence, two had committed family violence themselves, and five were known to the Corrections Department.
The cycle continued in the second generation of children. One of the woman's children had another seven children, six of whom were violent offenders or victims, and two of whom became gang members.
Mrs Collins said the case study was not an extreme example.
